Nitroglycerin (TNG) was administered to 15 patients with aortic regurgitation and left ventricular (LV) dysfunction determined by radionuclide cineangiography during supine exercise. TNG resulted in a 25% decrease in LV end-diastolic volume (LVEDV) during exercise (P is less than .01) with no change in exercise heart rate; TNG also resulted in a significant increase in exercise LV ejection fraction (40 plus or minus 10% pre-TNG to 47 plus or minus 10% post-TNG). Thus, despite reduction in LVEDV (causing reduction in wall stress), stroke volume diminished only 5% at maximal exercise. The TNG-induced reduction in LV wall stress with maintenance of external work may be of value in long-term management of patients with aortic regurgitation.